Motor let loose this AM!

[idM1028]

@diesel583 Good deal. I'm something of a pessimist so I tend to look at things with a "hope for the best, plan for the worse" mentality. I mean who knows? You could have this poor guys problem and have a bad harmonic balancer that leads to a total crank failure. The 6.2's are notorious for this. . .

 

[hre513]

Here's the Verdict.......the crankshaft broke just behind the second connecting rod. After reading throgh a few more threads it seems this might have happend because of a bad harmonic balancer.

Anyone know if the Crankshaft can be replace with the engine still in the vehicle?? Sure would be nice if I didn't have to pull it.

If your crank is broken you may have cracks in the main bearing webs also.

 

[rnd-motorsports]

besides you still have to pull trans loose and slide back and the front all has to come apart for the timing,Better to just pull it. Get it where you can work on it much nicer than laying on you back. Take it apart and see what you have before you buy some parts to fix something that is maybe not rebuildable! Sorry just saying now days better safe then sorry!

 

[mktopside]

Did you have any indication that the balancer was failing?

 

[hogtruck]

If you're not in a hurry, I have two engines in the can and two in parts trucks. However, leaving the country for three weeks. PM me for a phone number.
Regards,

 

[kentuckycucv]

i have seen hundred of 6.2l engins pulled from humvees from the military swapping out all of the 6.2l for 6.5 turbo diesels. They put the 6.2ls in the shipping crate the 6.5s came in. Piled them high and sold them on gov liquidations. Somebody is sitting on piles of used low mile moters.

 

[txmytx_catahoula]

Did you have any indication that the balancer was failing?

As far as I'm aware, I didn't have any indication it was failing. From what little I have read, the symptom are "a knocking sound and additional vibration". I've been around a few of these early production V8 diesels and I'm not sure I'd be able to notice any addition vibration or knocking. Looking at the balancer it doesn't exhibit any of the signs of deteriation that has been described as a "failing" balancer. I try to keep my eyes, ears and nose alert to my rides....this one just let loose. It really did sound like I'd blown 2 tires.

 

[txmytx_catahoula]

i have seen hundred of 6.2l engins pulled from humvees from the military swapping out all of the 6.2l for 6.5 turbo diesels. They put the 6.2ls in the shipping crate the 6.5s came in. Piled them high and sold them on gov liquidations. Somebody is sitting on piles of used low mile moters.

Copy that. I've seen just a few advertised on Ebay or craigslist. Most are "unknowns" but a couple of companies have "compression checked/ run" 6.2's available. Kind of wanted to work on this M1009 myself. Just not this much this soon!

 

[ken]

Craig, There is a guy named ben in groves that i have bought a few CUCV engines from. I can't rember the street name but he is just down the street from TOTAL. PM me and i'll get you his number.

 

[rickf]

I have seen a lot of 6.2's break in the same exact spot. A lot of the time it is from using ether. Could have been a balancer if you were really twisting it. Forget replacing the crank, the timing cover is going to be trashed and the front main journal will be either cracked or severely gouged. That motor is now a parts donor.

 

[rnd-motorsports]

Even the civilian models had the same problem.The cucv models just a bit more most likely because of the gears and being turned harder.GM tech bulletins lists the harmonic as the cause for the crank breaking mainly just in front of the # two main,Must be the week spot! the harmonic bal outer will spin a bit from the inner rubber will go bad.Most of the time you never know it, they just put the crank out of balance in a diesel its hard they vibrate anyways! But when the crank breaks you cant help but know it!

 

[txmytx_catahoula]

Picked a new motor, well 31K miles, in San Antonio last weekend. New harmonic balancer an gaskets/seals shoes up today. So the engine swap out begins!!!!! :-I

 

[Dave Kay]

Picked a new motor, well 31K miles, in San Antonio last weekend. New harmonic balancer an gaskets/seals shoes up today. So the engine swap out begins!!!!! :-I

Awesum! Glad to hear there is progress! Hope you get it done in good time and have a chance to post some pics/problems if encountered.

Been following this thread and it's gettin' me kind of nervous about my balancer. Like every time the engine sounds a little different I shut down and get under the thing and try pulling belts or wiggling something to see if that HB is going bad, or whatever... I think the only sure-fire fix if one is in doubt--- just replace it ASAP!

Good luck to ya' bud!

 

[patracy]

I wonder if fluidampr makes a damper that would fit a 6.2. I know they make them for the 5.9 cummins.

 

[hogtruck]

Part number 800191. Summit lists them for $435.35

 

[Gunnar1071]

Awesum! Glad to hear there is progress! Hope you get it done in good time and have a chance to post some pics/problems if encountered.

Been following this thread and it's gettin' me kind of nervous about my balancer. Like every time the engine sounds a little different I shut down and get under the thing and try pulling belts or wiggling something to see if that HB is going bad, or whatever... I think the only sure-fire fix if one is in doubt--- just replace it ASAP!

Good luck to ya' bud!

Never seen it on a CUCV, but on the 5.0s I have worked on, if you look across the face of it from the top or side, you will see the outside ring wobbling slightly.

 

[txmytx_catahoula]

Well the replacement motor is in! I went ahead and put a new balancer on and replaced the motor and trans mounts with poly. Shouldn't be just a few more days before the Blazer is making PROPER noise again. The culprit? Look at the balancer pic. The key was sheared flat.......so did this happen which caused the crank to snap or did the crank snapping cause the key to shear?? Chicken or the egg!

 

[chuck0070]

So if the Harmonic Balancer is bad... are they defective, the original ones? What make a new one any different, meaning what defect, if any, is cured?

 

[rickf]

The usuall failure is the rubber ring, it will degrade and allow the outer metal balancer to move in relation to the inner therfore changing the balance point. This is usually an age thinge and not really a defect. In your case I think there was more going on there. I would guess that at some time someone shot it with ether and the kick back sheared the key. Usually it will break the crankshaft right behind #2 rod journel. I did not read the whole post to see what had happened.

Rick

On edit, I went back and read the whole thread and I see where I had already chimed in on the ether and broken crank thing. Sorry for the redundancy. I answer a lot of posts on several forums and sometimes I get lost in space.

 

[chuck0070]

Fortunately I havent had this problem... but I do have 95,000 miles on my M1009. If there is a defect or sorts with the Balancer, I would rather have this addressed and do something preventative while it is running good than do the whole motor if it scatters.